This application is directed to novel reaction products of sulfur-containing diacyl generating halides, e.g., diacyl halides with phosphorodithioic acids and phenols or thiazoles which function as multifaceted additives when incorporated into lubricants and to lubricant compositions containing same.
Lubricants, scch as lubricating oils and greases, are subject to oxidative deterioration at elevated temperatures or upon prolonged exposure to the elements. Such deterioration is evidenced, in many instances, by an increase in acidity and in viscosity, and when the deterioration is severe enough, it can cause metal parts to corrode. Additionally, severe oxidation leads to a loss of lubrication properties, and in especially severe cases this may cause complete breakdown of the device being lubricated. Many additives have been tried, however, many of them are only marginally effective except at high concentrations. Improved antioxidants are clearly needed.
Antioxidants or oxidation inhibitors are used to minimize the effect of oil deterioration that occurs when hot oil is contacted with air. The degree and rate of oxidation will depend on temperature, air and oil flow rates and, of particular importance, on the presence of metals that may catalytically promote oxidation. Antioxidants generally function by prevention of chain peroxide reaction and/or metal catalyst deactivation. They prevent the formation of acid sludges, darkening of the oil and increases in viscosity due to the formation of polymeric materials. Additionally lubricants are under heavy stress that can affect their extreme pressure/ antiwear and load carrying ability particularly between steel on steel moving surfaces.
The use of phosphorus compound per se as load-carrying or EP additives in lubricant compositions is well known. Also, the use of sulfur-containing compounds in lubricant compositions is well known. However the instant combination of sulfur, phosphorus and phenol or thiazole containing additives to the best of applicants' knowledge was heretofore unknown.
It is an object of this application to provide lubricant compositions having enhanced oxidative stability, reduced wear, increased load carrying/EP capabilities and improved lubricity.